1. Field of the Invention
The present invention relates to a fuel storing device for a motor vehicle.
2. Description of the Related Art
Known in the art is an internal combustion engine which prevents the discharge into the outside air of the fuel vapor produced in a fuel tank when refueling by leading the fuel vapor in the fuel tank into a charcoal canister at the time of refueling so as to cause it to be adsorbed in the charcoal canister. In this case, if there is too much of an amount of fuel vapor produced in the fuel tank at the time of refueling, it is necessary to make the charcoal canister larger in volume. To make the charcoal canister smaller in size, it is necessary to reduce the amount of the fuel vapor produced in the fuel tank as much as possible.
However, when fuel sits in the fuel tank, the upper space in the fuel tank becomes filled with fuel vapor. Accordingly, to reduce the amount of the fuel vapor produced in the fuel tank, it is becomes necessary to reduce the volume of the upper space in the fuel tank as much as possible. Known in the art is a fuel tank wherein, to reduce the volume of the upper space of the fuel tank, a separating film contacting the surface of the liquid fuel in the fuel tank and moving up and down with the surface of the liquid fuel is disposed in the fuel tank and a plate serving as a weight is placed on the separating film (see Japanese Utility Model Publication (Kokai) No. 60-158922).
If a weight is used in this way, however, not only is there the problem of the fuel tank becoming heavier, but also there is the problem that the construction of the fuel tank becomes complicated, so time is taken for fabricating the fuel tank.